Modulable electric discharge lamp



E. LEMMERS IODUIQABLE ELECTRIC DISCHARGE LAIP July 20, 1948.

Original Filed Feb. 12, '1942 EUGf/VE L'EMMERS H5 Arm/z/vi explained.

Patented July 20; 1948 FFICE 2.445.010 Mon'ULAnu: anac'rmc mscna'ma LamEugene Lemmers. Cleveland Heights, Ohio, u-

Ilmor to General ration of New York Original application Feb Divided andthis Serial No. 551,793

No. 430,598. at 30, 19,

eotrio Company, a co f 12, 1942; Serial application An- -1 cum. (c1;176,-122) This invention relates to the'modulation of an ectricdischarge, and is especially concerned known as crater lamps."

is application is a division of my application Serial No. 430,593, filedFebruary 12, 1942, in which is described and claimed lamps of thepositive column type, whereas the lamps specifically disclosed andclaimed in this application are of the well known negative glow type.

Various arrangements and constructions may be employed, several of whichwill be illustrated and Still other features and advantages oi theinvention will appear from the following description of species andforms of embodiment, and from the drawings.

In the drawing, Fig. g-rammatic view of a lamp comprising myinvencircuit,-

through a power circuit H, the the amplifier output circuit i2.

As shown in amplifier T, and

electrode 23 extends inside the flange of the anode structure.

f r-s tive in the sense outside the envelope 20, and also a portion ofthe circuit il.

In operation, the discharge current in the lamp L is proportional to thesignal intensity from S. The intensity of the endwise radiation from thedischarge toward the receiving system R depends on the dischargecurrent. In the absence of the anode means 23 with its connection 25,the intensity of the discharge would vary in sole dependence of thedischarge current. However, the resistance 26 in the connection 25 makesthe part 23 an anodeof lower'potential relative to the cathode is thanthe main anode i6, so that part of the discharge goes to this part 23,diminishing its end-on intensity of radiation. The degree to which thistakes place depends on the magnitude of the resistance 26 in theconnection 25, as well as on the position of the part 23. If theeflective resistance 26 were zero, all the discharge would go to thepart 23; if it were infinite, or, virtuallyso. all the discharge wouldgo to the main anode IS. The positive potential of the part 23 relativeto the discharge within it depends, of course, on the value of theresistance 26, and can be increased by reducing this resistance, andvice versa. I

Whatever the value of the resistance 26, the effect of the part 23 andthe connection 25 on the current-light curve of the device issubtracthat the light for a given discharge current flowing in thecircuit I1 is reduced. Naturally, this effect is proportionally greaterfor low currents, since the smaller the current flow, the greater'theproportion of it that can be accommodated by the path via the part 23and the resistance 26, which gives rise to a lower intensit of radiationthan an equal current via the main anode i6. Accordingly, .the lower endof the current-light curve is depressed very greatly in proportion toits height above zero, while the upper end affected. Thus the connection25 with its resistance 26 makes the end-on intensity of radiation towardthe receiving system It vary in a greater ratio than the dischargecurrent, and this ratio can be altered by adjusting the resistance 26.

Fig. 2 illustrates diagrammatically a somewhat different type of craterlamp oi! the negative glow type also embodying the invention. Here thecathode 15a consists of a hollowed cylindrical metal body enclosed in aninsulative sleeve ll with an internal flange 42 covering one end of thebody i5a around the mouth of its exposed of this curve is scarcely majorcathode hole 40a. The mouth of a minor cathode hole 43 in the other endof the body is also exposed. The main anode i6a has the form of a sheetmetal-cap over and around the flanged end of the insulator 4|, centrallyapertured in axial alignment with the major hole 40a, while the otheranode 23a has the form of a sheet metal cap over and around the otherend of the insulator 4| and cathode lid, with a central metal boss 45projecting into the minor hole 43. The circuit connections areessentially the same as shown in Fig. l, and are marked with the samereference characters, as a means of dispensing with repetitivedescription.

The embodiment of applicants invention shown in Fig. 2 is being claimedin copending patent application Serial No. 787,117, filed November 20,1947, and which is assigned to the assignee of this application,

What I claim as new Letters Patent of the United States is:

A modulable gaseous electric discharge lamp of the negative glow typecomprising a sealed envelope containing an ionizable medium, a hollowcathode having an internally electron emissive bore, an annular sheetmetal anode in front of said cathode and aligned axially with said boreand having a flange extending toward said cathode, and a shell-shapedsheet metal control electrode closely surrounding and enclosing thesides and back end of said cathode. and extending inside said flange.

EUGENE LEMMERS.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,834,072Schroter "Dec. 1, 1931 1,834,251 Moore Dec. 1, 1931 1,912,097 Rinia May30, 1933 1,915,934 Holst June 27. 1933 1,923,051 Case (a) Aug. 15, 19331,932,078 Knowles Oct. 24, 1933 1,951,143 Foulke Mar. 13, 1934 1,951,808Smith Mar. 20, 1934 1,970,223 Case (b) Aug. 14, 1934 1,999,649 BrettApr. 30, 1935 2,055,753 Schnitzeler Sept. 29, 1936 2,190,303 BlackburnFeb. 13, 1940 and desire to secure by

